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Friday, January 27, 2012

I have compiled the projects under MS Windows, surprisingly almost everything worked as expected and the binaries are available in Downloads(-RPGServer / Client / Bot Tutorial ->Windows Binaries), feel free to download and test it.

There were only two problems:

Server include paths were wrong, I had <SDL/SDL.h> so I replaced them with <SDL.h> and compiled fine

The bot was giving me errors in the line srand(time(NULL)), solved with a #include <time.h>, curious it worked fine under linux.

When running there is only an issue: no cout output under windows so server starts, and actually works! but there is no output at all, anyway it's ok to test.

The server has certain limits like not being able to accept more than
1018 clients and to use too much resources, but if you plan to work with
a limited amount of users (200-300) it will make the job.

I would be glad to hear (constructive) comments about the code, the bugs you may found and well, basically your opinion.

After I decided to stop the development for a while I tought it would be nice to share the code with everybody interested, so after a huge cleanup (probably not enought) I have uploaded the code for the server, the client and a silly bot I did to test multiple client connections, they are now in Downloads (-RPGServer / Client / Bot Tutorial -> Source code), feel free to download and test it.

The server has certain limits like not being able to accept more than 1018 clients and to use too much resources, but if you plan to work with a limited amount of users (200-300) it will make the job.

Server is untested under windows (it works!), client and bot wont care too much for the OS (will work in linux / windows), I don't have a machine with Mac OS X to test so I couldn't test it (any volunteer to try with an apple computer?)

I would be glad to hear (constructive) comments about the code, the bugs you may found and well, basically your opinion.

Tuesday, January 3, 2012

After a long time trying to fix errors / improve performance I have arrived to a sad point: My server with blocking sockets wont support more than 1.018 users, I arrived that limit making an stress test trying to arrive to the 2.000 users barrier, no more clients were accepted after client 1.018.

The problem comes from the design I choose to make the server, I was using blocking sockets, that means for every client we need a thread to wait for data, 1.018 users = 1.018 threads + threads used by the server reached the default limit in Linux (1.024), I have been reading about that , and I know that limit can be modified but it's not a real solution for the problem because my test computer used 90% processor time to handle "only" 1.000 users, so I have to switch to another technology..

That technology is non-blocking sockets, because basically with a single thread you could theoretically handle 1.000 maybe 2.000 connected users, I have been speaking with people that has worked in the game industry and for linux servers the best / fastest way is to use epoll , epoll is basically used to handle I/O from many file descriptors (connections) in real time, but using epoll to me would have meant throwing away all what I have been working on in the last 3 months.... (Thanks Neils for showing me the right way!)

Finally I decided to use socket sets , that is the SDL_net non-blocking approach for that problem , so basically I have to re-write all the networking code for my server...

I have decided to take a rest in the development and I have started a collaboration with a friend to make a multiplayer platformer, it is very good because I have time to think in other things and learn, I'm just finding that I was making many errors and many things could be improved.